EMRFD Message Archive 5535

Message Date From Subject
5535 2010-12-23 14:34:15 ae5ew Ferrite mix 31
Hi everyone. I'm new here and hoping to get some useful information. I have read back about 500 posts so far. Not certain if I'm going to read all 5,000. lol.
I have done a lot of studying of the choke articles in ARRL Handbook 2009. Interesting graphs of some analysis of some mix 31 toroids for feedline chokes. My concern. Well, it appears mix 31 is being retired. I'm not certain if mix 77 is taking its place, or, something else.
Comments? TIA
Charles AE5EW
5536 2010-12-23 14:48:24 Tim Re: Ferrite mix 31
The mixes get "reformulated" sometimes without changing their number. (I think I've heard folks talk about "old mix" and "new mix" with respect to either #43 or #77.)

I thought 31 was the NEW "extra broadband" EMI mix introduced just a couple of years ago and all the rage since then. e.g. http://www.mouser.com/catalog/catalogUSD/642/952.pdf

5538 2010-12-23 14:56:48 ae5ew Re: Ferrite mix 31
Fair-Rite doesn't even mention ferrite mix 31 in their current literature. I have seen mention of the reformulati
5540 2010-12-23 16:36:51 Jim Miller Re: Ferrite mix 31
I just found 31 mix on their website. Where did you fail to find it?

jim ab3cv

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5541 2010-12-23 17:00:47 Mike Mayer Re: Ferrite mix 31
Here's a good resource that advocates mix 32 for common model chokes:


Mike Mayer

-----Original Message-----
5543 2010-12-23 17:25:09 ae5ew Re: Ferrite mix 31
with their toroid discussions/pdfs
Charles AE5EW

5544 2010-12-23 17:58:14 Jim Miller Re: Ferrite mix 31
mix 31 is intentionally lossy and consequently probably not good for
toroidal inductor use rather best used for emi suppression.

it's all over their website.

jim ab3cv

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5545 2010-12-23 19:05:59 ae5ew Re: Ferrite mix 31
Excellent informati
5546 2010-12-24 05:09:38 ae5ew Re: Ferrite mix 31
Doh! I took a much close look at their catalog. They are there. Guess I missed them somehow. Visual block? I also thought mix 77 was for higher freqs. Hmmm.
Charles AE5EW

5547 2010-12-24 05:47:53 ae5ew Re: Ferrite mix 31
After going through their product catalog three times slowly, I can't find any mix 31 for Toroids. It just isn't listed. Since I was specifically looking for Toroids, I hadn't looked through the rest of the catalog before. In the secti
5548 2010-12-24 05:52:38 ae5ew Re: Ferrite mix 31
And, mix 31 is not listed at:
So, I'm a tad bit confused
Charles AE5EW

5550 2010-12-24 08:06:26 Tim Re: Ferrite mix 31
"Bead" vs "Toroid" is a fuzzy line.

The marketing term these days seems to be "round cable EMI suppression cores". Click on this in the Amidon search engine. They're cheap and plentiful and make wonderful toroidal cores.

Keep in mind that perhaps the most popular mix 43 toroid core of all time, used by me like popping a Pez in all my homebrewing, is sold by Mouser not as a toroid but as a "EMI Shield bead": Mouser 623-2643002402 (sort of an overlong FB37-43). Mouser has a very decent selection of Fair-Rite ferrite toroidal cores (usually called beads) and binocular cores but the Amidon terminology isn't used in their search engine. Starting from the Fair-Rite catalog and typing a part number into Mouser is EXTREMELY productive. They even have many binocular cores.

recommended pages in Mouser catalog: http://www.mouser.com/Catalog/catalogusd/642/952.Pdf

Recommended pages in Fair-Rite catalog: Pages 69-70

Hams have a long tradition of finding what is available and plentiful and using it as a ham radio part despite it not being marketed as such. The parallel feed line with hair curler spacers was always my favorite. The marketing push for 31 mix is definitely EMI suppressi
5551 2010-12-24 09:47:50 Mike Mayer Re: Ferrite mix 31
There are some type 31 listed under:

Products->Cable Components->Round Cable EMI Suppression Cores

Products->Cable Components->Round Cable Snap-Its

Mike Mayer

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5552 2010-12-24 10:24:25 Derward Myrick Re: Ferrite mix 31
Charles, I have some toroids that are mix 68. Goodn to 100
mhz. It is in their cat.

If you are interested give me a call at 281-1842.

Derward Myrick KD5WWI

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5555 2010-12-24 22:52:04 Derward Myrick Re: Ferrite mix 31
Charles, check out this link it gives you all the mixes
they have.

Derward Myrick KD5WWI

----- Original Message -----
5557 2010-12-25 00:14:30 ae5ew Re: Ferrite mix 31
I checked it out. I believe I had already seen in during research. Nothing is mentioned for mix 31 for Toroids. Mix 43 specifically states it is used for Toroids and it is in fact listed in their catalog under Toroids. Several companies sell mix 31 Toroids so I'm still confused about Fair-Rite actually still manufacturing mix 31 Toroids. I not trying to be difficult. Just confused.
Charles AE5EW

5560 2010-12-25 02:13:58 ae5ew Re: Ferrite mix 31
Ok, for some reason Fair-Rite doesn't list mix 31 toroids, but,
Round Cable EMI Suppression Cores, they are listed here for 2.4 od cores. Part Number: 2631803802 .. Fair-Rite doesn't list a 1.4 od mix 31 core in this table. There must be some kind of distinction between Toroid and Suppression Core.
Charles AE5EW